jase
29-04-2008, 08:26 PM
Hi All,
I tribute this image to my father who lost his battle with illness on Sunday night. You’ll be greatly missed - May you wander amongst the imperishable stars.
Here is my latest effort, the bi-polar emission nebula NGC6164-6165 (http://www.cosmicphotos.com/gallery/image.php?fld_image_id=144&fld_album_id=11). A wide field rendition of the fascinating Ara OB1 region showing the location of NGC6164-6165 relatively to NGC6188 can be seen here (http://www.cosmicphotos.com/gallery/image.php?fld_image_id=103&fld_album_id=11).
Located in the constellation Norma, the S-shaped bi-polar emission nebula (NGC6164-6165) forms part of the greater Ara OB1 region. Originally believed to be a planetary nebula, NGC6164-6165 is the result of ejected matter from the poles of the central Wolf-Rayet type star (HD 148937) as it passes the main sequence life cycle. Due to the star's fast rotation, magnetic field and violent winds, the gas is being expelled in a symmetric manner. While the nebulosity appears connected, the object has been granted two NGC catalogue numbers. In the image presented, NGC6164 is located at the bottom, while NGC6165 at the top. The nebula is estimated as being 4,000 light years away. To the right of the central blue star in the image (SOA 226920) is the small open cluster designated SAC Ru 120.
A few words on the image;
The image is an R[Ha+R]GB composite totaling 5.5 hours (R:120min-1x1, Ha:75min, RGB:45min each). Data acquired on GRAS008. Processed using Registar, MaximDL and PS. I decided on using red filtered exposures as the main luminance data. This was acquired over the recent full moon period as red filtered (like Ha) are relatively unaffected by the moon (which emits predominately in the blue wavelengths). I collected two sets (1x1 and 2x2) of red filtered data. On reflection, I could have easily used the 1x1 data for the RGB as well, just scaled up the G and B channels. I acquired more Ha data, but found subs were extremely noisy so many were omitted. I suspect this was related to the calibration frames. I think the image screams for more Ha data to further bring out the shock waves. I blended a considerable amount of red channel data into the Ha to reduce the noise using the lighten mode – slight trade off. Background is a little noisy, so could have perhaps been a little harder in the reduction process. Minor gradient corrected in the blue channel using GradientXTerminator. Seasoned to taste.
Imaging soothes ones soul in time of need.
Hope you like it. :)
I tribute this image to my father who lost his battle with illness on Sunday night. You’ll be greatly missed - May you wander amongst the imperishable stars.
Here is my latest effort, the bi-polar emission nebula NGC6164-6165 (http://www.cosmicphotos.com/gallery/image.php?fld_image_id=144&fld_album_id=11). A wide field rendition of the fascinating Ara OB1 region showing the location of NGC6164-6165 relatively to NGC6188 can be seen here (http://www.cosmicphotos.com/gallery/image.php?fld_image_id=103&fld_album_id=11).
Located in the constellation Norma, the S-shaped bi-polar emission nebula (NGC6164-6165) forms part of the greater Ara OB1 region. Originally believed to be a planetary nebula, NGC6164-6165 is the result of ejected matter from the poles of the central Wolf-Rayet type star (HD 148937) as it passes the main sequence life cycle. Due to the star's fast rotation, magnetic field and violent winds, the gas is being expelled in a symmetric manner. While the nebulosity appears connected, the object has been granted two NGC catalogue numbers. In the image presented, NGC6164 is located at the bottom, while NGC6165 at the top. The nebula is estimated as being 4,000 light years away. To the right of the central blue star in the image (SOA 226920) is the small open cluster designated SAC Ru 120.
A few words on the image;
The image is an R[Ha+R]GB composite totaling 5.5 hours (R:120min-1x1, Ha:75min, RGB:45min each). Data acquired on GRAS008. Processed using Registar, MaximDL and PS. I decided on using red filtered exposures as the main luminance data. This was acquired over the recent full moon period as red filtered (like Ha) are relatively unaffected by the moon (which emits predominately in the blue wavelengths). I collected two sets (1x1 and 2x2) of red filtered data. On reflection, I could have easily used the 1x1 data for the RGB as well, just scaled up the G and B channels. I acquired more Ha data, but found subs were extremely noisy so many were omitted. I suspect this was related to the calibration frames. I think the image screams for more Ha data to further bring out the shock waves. I blended a considerable amount of red channel data into the Ha to reduce the noise using the lighten mode – slight trade off. Background is a little noisy, so could have perhaps been a little harder in the reduction process. Minor gradient corrected in the blue channel using GradientXTerminator. Seasoned to taste.
Imaging soothes ones soul in time of need.
Hope you like it. :)